Show notes for episode 185, February 10, 2014
Hosts: Paul, Hugh
Title: Meteors, Mars and beyond (to Tantooine!)
From the far flung visions of Galileo and Jules Verne, stopping off briefly to check up on Curiosity (and the latest “hole” on Mars), we finished the show by discussing the exciting research about circumbinary stars and the ability for exoplanets to survive amidst such ravaging gravitational influences.
This week in space/astronomy history:
1. Galileo Galilei, 15 February 1564 – 8 January 1642. Arguably one of the most notable astronomers, indeed scientist’s in history. Amongst other accomplishments, he is one of the first to record observations of the night sky with the newly invented telescope.
2. Jules Verne, French science fiction author, 8 February 1828 – 24 March 1905.
3. Chelyabinsk meteorite event, February 15 2013. 17-19 metre meteor weighing in at about 12,000 tonnes exploded above the city early in the morning. Over 1,100 people injured by breaking glass from the shockwave.
4. In 1990 on Valentine’s day February 14th Voyager 1 turned back around and captured images of our solar system in a “family portrait” of our celestial home. This is the infamous “Pale Blue Dot” picture that Carl Sagan asked to be taken.
1. ISS update: Progress 54 docked Feb 5 and science continues to be carried out throughout the station. It is both satisfying and sad (in a way) that the routine operation of ISS drops from view. Have we really entered an age where exploits in LEO are indeed “ho hum”? Think back to our brief chat earlier about Jules Verne. www.nasa.gov
2. Curiosity update: Curiosity is still chugging away on Mars, this week it crested a dune and is now deciding whether to continue through the Dingo gap, it has provided some stunning pictures of some interesting geological features that look strikingly similar to dried up riverbeds here on earth. Curiosity also snapped its first ever picture of earth on Thursday; from 99 million miles away the Earth and our Moon both appear as two shining dots in the sky that would be visible even to human observers standing on the surface!
3. Mars gets hit by meteor
Really just a stunning image. Perhaps not useful for actual story. Happened sometime in the last few years, spotted by the MRO, crater is 30m in diameter and debris was flung up to 15 km away!
4. Oldest star discovered (pop II!)
Discovered by Astronomers at ANU (Shoutout to Australia, Paul!) It’s located 6000 light years from earth and would have formed from a population III star of mass ~60 Msol. The star is at least 13 billion years old although we cannot be certain of an exact age. We can determine however that it is a pop II star due to its incredibly low Iron content, less than one millionth of the iron in our own sun! The star is polluted much more heavily by carbon which is why the researchers have been able to determine that it would have formed from the remnant of a slightly lighter population III star (i.e. the 60 Msol figure)
5. Brief mention of Yutu–Not much to talk about, apparently we’ll know whether or not it has survived by 2am tonight, according to the fan run account on weibo. I have been following it on twitter all day but to no avail since it seems that yutu is slang for something in spanish.
6. Canada govt releases long term plan for space, something that has been in the works since 2008. It’s a bit high level, the CSA is expected to come out with a more technical document later in the year, but for now we know that the astronaut program will continue to be funded! (Good news for wannabe astronauts such as myself) The CSA will also unsurprisingly push more towards the private sector, which is a growing industry in Canada, as well as remain firm on its commitment to provide the fine guidance system for the JWST in 2018. Personally what I see in this is more of the shifting of priorities for the CSA away from being a research body and more towards being an agency devoted to technical innovation–I expect that the CSA will continue to provide funding and technical expertise to research missions but the actual science will be farmed out to participating institutions.
Major Topics Discussed:
Cirumbinary star systems: how planets can form around binary stars. recent studies for 2 Kepler star systems, 34 and 413 and suggesting that planetary formation “from afar” followed by migration can lead to planets surviving close to the parent stars.
Kepler 34b investigated out of the U of Bristoll (UK). At 4900 light years distant, 34b transits every 289 days (1.09 AU out). Binary stars eclipse every 28 days. Computer simulations suggest that the planet had to have migrated inwards from 1.5 AU or more. Too “dangerous” closer in to have formed.
Kepler 413b, 2300 light years away, has a precessing orbit and is transiting every 66 days up to … well, no more transits for 6 years! Unclear why the orbit precesses. Variation in energy received at the planet is from .9 to 2.7 times what Earth receives from the Sun The planet also precesses on its axis up to 30 degrees every 11 years! Huge seasonal variation.
There’s a recent paper from researchers at McMaster and Weber State University that seeks to break out of the earth centric habitable zone that Astronomers are so fond of,well, inhabiting. Their major theories are that the most habitable planets, or planets where life would be most likely to thrive are actually 2-3 times the mass of earth and would orbit K-Dwarf stars. The larger size of the planet has a host of beneficial factors such as retaining a thicker atmosphere and stronger magnetosphere, reducing tectonic plate movement, evening out the surface of the planet leading to warmer, shallower seas which are more conducive to early life. Furthermore the large size of the planet and low mass of the sun would result in a much greater overall lifetime, with larger periods of stability than our own planet. In my view it’s an interesting paper simply because it counters the tendency of Astronomers to assume that because Earth has life, earth must be the perfect place for life to flourish.
S. Lines et al. “Forming Circumbinary Planets: N-Body Simulations of Kepler-34.” Astrophysical Journal Letters, 2014
V.B. Kostov et al. “Kepler-413b: a slightly misaligned, Neptune-size transiting circumbinary planet.” Astrophysical Journal, 2014
Thanks for listening!
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